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10.4: Boot Intel Macs from iPods and FireWire drives System 10.4
Tiger only hintCurious about how to booting your Intel iMac from either a USB2.0 iPod or an external Firewire drive? It is possible, and here's how. This has been tested with a 5G 30GB USB2.0 iPod with Video and an external FW400 60GB hard disk enclosure.

The key issue is the disk partioning scheme that Intel Macs expect to see. GPT (or GUID), remember? Well it appears that the EFI in an Intel iMac also supports booting from Apple Partition Map (APM) partitioned disks as well. The Intel iMac's Install DVD Disk One, for instance, uses an APM and NOT a GPT scheme.

So how to fool the system and it's hardware? Credit due to Joel and the TidBits article (referenced in this earlier hint) for setting the germ of the idea in my mind.

Take a current 5G iPod USB2.0 and restore it as though new, using the iPod Updater with the iPod connected to an Intel iMac (this part probably isn't necessary). Interestingly, while the iPod updater itself is a Universal Binary, the Restore function creates an APM partitioning scheme on the iPod when you restore it.

So how to get Mac OS X 10.4.4 (Intel) onto the iPod? I still wanted to use the iPod for Music and Video, so erasing and partitioning were not allowed; it had to be single volume. And you can't select this volume as the installation destination while booted from Install DVD, because the installer doesn't like its partition map.

ASR (Apple Software Restore) to the rescue (and the following was done on a live system):
  1. With iPod connected and mounted on the Desktop, open Terminal.

  2. At the prompt type the following:
    sudo asr -source /Volumes/imac_boot -target /Volumes/ipod_name
    Replace imac_boot with the name of your iMac's boot disk, and ipod_name with the name of your iPod as seen on the Desktop. If you are unsure, do an ls /Volumes first to see the proper names. Then press return once and authenticate.

    This will clone the internal boot disk system to the iPod. How long will it take? My boot disk had roughly 8.5GB of data. Cloning that with ASR took around 25 minutes.

  3. When the clone completes, you will probably get a message in Terminal about the System on the iPod not being blessed. I did, but the fix is easy. Just type the following, then press Return and authenticate when asked:
    sudo bless -folder /Volumes/ipod_name/System/Library/CoreServices
  4. Now go to the Startup Disk System Preferences pane, and verify that you can see the iPod listed as a valid boot disk. Select it and gently click Restart. Startup is slower than booting through Firewire from a 3G iPod on PPC Mac, but it works.
But consider what you have just done? Succesfully booted via USB2.0 from an iPod using an OS X Intel system on a disk formatted with the Apple Partition Map. That is not supposed to be possible, but it would appear that it is. Getting carried away, I then decided I would have cake and eat it, too!

I use an external FireWire drive for system troubleshooting, and it was already partitioned and had a current version of 10.4.4 for PPC on one partition, with applicationss and backups only on the other chunk. Just follow the same steps as above, and you will get the same result.

The beauty of this solution is that you now have an external FireWire disk that will boot either current PPC hardware or current Intel iMac hardware from different partitions on the same physical disk, using an Apple Partition Map partitioning scheme. Simply select the appropriate partition when doing an option key (Startup Manager) boot. In fact, you should only see one of the two partitions anyway, as one of the two available systems will not work with the connected hardware.

Run Repair Permissions from within Disk Utility after testing. I didn't find anything amiss, though there seem to be awful lot of the "we are using special permissions" type messages. These appear everytime you run Repair Permissions, and are not related to the cloning job you've just performed. A check of the system.log file post-boot off the iPod also showed nothing out of the ordinary either.

Caveats? No warranties, guarantees expressed or implied. There may be, as yet, uncovered issues. Proceed at your own risk as always.
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10.4: Boot Intel Macs from iPods and FireWire drives | 13 comments | Create New Account
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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: CHerbold on Feb 22, '06 01:57:04PM

Just a side note but I have personal Knowledge how to boot some of the last rev ppc macs through USB 2.0 using the APM, Unfortunalty I have not gotten my hands on the Intel Macs to play around but great to know the information you provided. THANKS,


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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: AndyTim on Aug 17, '06 03:57:07PM

Are you talking about some special technique involving Open Firmware? As I understand it, when trying to boot many Macs to a bootable iPod partition like this:
0 > boot usb0/device/disk:3,\\:tbxi
Or anything similar, we get a RESET-PORT or something like... A timeout? Can you supply the information you mentioned about booting some PPC Macs please?

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Boot from APM drives
Authored by: aqsalter on Feb 22, '06 05:35:27PM

If we can boot from APM external drives, does this mean that we can boot from the internal drive APM?
Isn't that a major hold up in the dual-boot problem?

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Boot from APM drives
Authored by: kurnelpanik on Feb 28, '06 10:20:29PM

Heh that was what I tried after doing the iPod and FW boot trick;-)

Yep you can. Intel iMacs will boot from their internal drives if they're formatted with APM partitioning schemes rather than GPT. So EFI DOES support booting from both partition maps. Had to as the Install DVD you get is APM formatted

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: jdmuys on Feb 23, '06 01:38:22AM

Interesting, but I have a problem: on one of two Macs I use, there is no "bless" command. Both Macs have OS X 10.4.5. Any idea what could have happened?

I tried with and without sudo. "locate bless" didn't.

I have installed the developer tools (XCode 2.2), though on another partition through a symbolic link.

bless is supposed to be in /usr/sbin/. It isn't. There is exactly one other command missing from there: diskutil.

I am puzzled. Any idea what could have happened?



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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: kurnelpanik on Feb 28, '06 10:27:49PM

No but I have seen this phenomena myself on a system recently but cannot for the life of me remember the circumstances. It may be related to the installation of the Dev Tools but I cannot be sure of that. If I find out why this happens "sometimes" I'll pass the info back through here.

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: boli on Feb 23, '06 02:07:10AM
According to this article, instead of using asr - the CLI version of Apple Software Restore - one could also just use Disk Utility's "Restore" feature - a GUI for asr.

The article says that block-copy mode is needed, which means that both the source and target disk must be able to unmount. This in turn means one must boot from yet another volume - the Mac OS X DVD should do I guess. Also: check "Erase Destination" to allow block-copy mode.

That may sound like more work than cloning a live system in Terminal, but a block-copy is considerably faster, and personally I'd feel more comfortable than cloning a live system.

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: pmccann on Feb 23, '06 05:14:05AM

Yep, this is pretty much what I've found. Just grab, say, another mac ("mac2") and boot the intel mac in firewire target mode (hold down t when booting it, with a FW cable connecting the intel mac to mac2). Mount the FW disk onto which you wish to clone the intel mac, and use Disk Utility to Restore the intel mac's volume to one of the partitions of the FW drive, with erase destination clicked. Block copying works its considerable magic, and the cloned partition on the FW drive will boot an intel machine.

Much easier than I'd expected given all the early talk.


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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: kurnelpanik on Feb 28, '06 10:25:06PM

agree regarding block copy mode but the fly in the oinment is as follows. If you use Disk Utilities Restore function while booted from the Intel iMac's Install DVD and you opt to erase then you will get a GPT partition map by default. For this mod to work the Intel iMac would need to be in TDM and connected to a PPC Mac with the source image accessible.
Thanks for the feedback though.

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: boli on Apr 10, '06 03:15:30PM
admittedly i have no personal experience with an intel mac, but i verified the following on my PPC mac (quad G5):

checking "erase destination" before restoring simply enables blockcopying - otherwise it will do a regular recursive file copy. the target partition table will not be overwritten in either case. if it would, then any other partitions on the target disk would be lost.

DiskUtility in 10.4.6 allows even PPC macs to create disks that use GPT, i was able to test blockcopying a 5.5 GB partition off a multi-partition disk (that used APM) onto a single partition on an external 80 GB firewire disk. the target disk was previously partitioned into a single journaled HFS+ partition using a GUID parition table (GPT). this is still the case after the blockcopy. the target disk was "bonsai", the source (5.5 GB partition of a 400 GB disk) is not shown.

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: BSS on Mar 15, '06 10:43:36PM

I have an external Firewire hard disk formatted and partitioned on a PowerPC Mac and has Mac OS X Tiger on one partition. I'm using it to boot from any PowerPC Mac.

Here's the dilemma. I wanna use it to boot on an Intel Mac too. As far as I understand, it can't be done.

Now, what I really need is to have an external Firewire hard disk with one Mac OS X Tiger so that I can use it to boot on an Intel Mac or a PowerPC Mac.

How can this be done?

Sorry for asking a noob questions.


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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: UberFu on Sep 24, '06 01:52:16AM

So ultimately - we cannot set up an external firewire drive -

- create 2 partitions
- and be able to boot one parttition on a PPC Mac and a second partition on an Intel Mac_

However - either partition scheme will mount and show up on both PPC and Intel as standard storage volumes_

That's what I am reading here ?

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10.4: Boot Intel Macs from iPods and FireWire drives
Authored by: freepms on Mar 29, '07 05:51:00PM

Paul McCann's technique works. Partition a FireWire drive as APM, install PPC Tiger on one partition. Boot an Intel Mac in FireWire Target mode, connect it and the external to another Mac (I used an Intel Mac Mini and an iMac G5). Use Disk Utility to restore the Intel Mac's drive to an empty partition of the FireWire drive, with the Erase Destination and Skip Checksum options both checked. Voila, a FireWire drive that will boot either a PPC or an Intel Mac.

In my testing, the Intel partition also shows up when Option-booting a PPC Mac (a PowerMac G5 dual). Select it and proceed with the boot, and it grey-screens almost instantly. But the PPC partition does not appear when Option-booting my Intel Mini.

This is close enough to a universal boot drive for my uses.

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